Reciprocating electromagnetic pump



.June'9, 1953 K o. AUMICK ETAL 2,641,138

RECIPROCATING ELECTROMAGNETIC? PUMP Filed Aug. 23', 1951 IN V EN TOR.

{Zr/u WITNESS I v Patented June 9, 1953 RECIPROCATING ELECTROMAGNETIC PUMZP K. Donald Aumick, Pine City, and John W. Dickey, Newfield, N. Y., assignors to Bendix Aviation Corporation, a corporation of Dela.-

ware

Application August 23, 1951, Serial No. 243,332

The present invention relates to a reciprocating electromagnetic pump, and more particularly to a pump of this character for supplying liquid against substantial back pressure.

Electro-magnetic piston pumps in which the piston is constituted by a magnetic plunger forming the core of a solenoid, as shown for instance in the patent to Dickey et al. 2,472,067 issued June 7, 1949, have proved quite satisfactory when used to supply liquid such as fuel for an internal combustion engine against low back pressure in the order of three to six pounds per square inch. When it is desired to pump against higher back pressures, however, difiiculties arise due to the fact that if the piston is reduced in diameter, the available operating force is correspondingly reduced, while if the ampere-turns of the solenoid are increased the cost of constructing and operating the pump is also increased out of proportion to the advantage gained.

It is an object of the present invention to provide a novel electro-magnetic reciprocating pump of the directly-connected piston type capable of supplying liquid under substantially higher pressure than existing commercial pumps of that character.

It is another object to provide such a pump which involves only comparatively simple modifications of existing commercial structure, retaining the advantages of the latter while enlarging the field of use.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawin in which the figure is a vertical substantially midsectional view of a preferred form of the invention, the electrical system shown diagrammatically.

In the drawing there is illustrated a cylinder I of non-magnetic material in which a hollow magnetic plunger 2 is slidab-ly mounted. A solenoid 3 surrounds the cylinder I and is provided with magnetic pole pieces 4 and 5 fixed within a casing 6 of magnetic material which encloses the pump mechanism.

The pole piece 5 constitutes a partition which forms an inlet chamber I, and a partition 8 in the upper part of the casing 6 defines an outlet chamber 9. The pole piece 5 and partition member 8 have sealed connections with the ends of the cylinder I as illustrated at II and I2 respectively, so that the cylinder forms a conduit connecting the chambers.

A cup member I3 having an inlet check valve 2 Claims. (Cl. 103-53) down the plunger against the pressure of the spring I6 is provided including a battery I8 grounded at I5 and connected through a manual switch 2| to a lead 22 which is connected to one terminal of the solenoid. The opposite terminal of the solenoid is connected by a lead 23 to a fixed contact 24 which cooperates with a moveable contact 25 which is grounded at 26 to complete the circuit.

Contacts 24 and 25 are operated magnetically by the plunger 2 in the manner described in the patent to Dickey et a1. above cited, so that further description is deemed unnecessary.

A pump cylinder 21 of substantially smaller diameter than the cylinder I is located in the cup member I3 and is provided with a flange 28 forming a seat for the lower end of the spring I6, whereby said spring serves to press the flange 28 against the bottom of the cup. In order to permit a slight amount of universal movement of the cylinder 21, the lower surface of the flange 28 is formed with a spherical curvature, and a sealing washer 29 conforming thereto is seated in the bottom of the cup I3.

A hollow piston 3| having a sliding fit in the cylinder 21 is attached in any suitable manner as indicated at 32 to the lower end of the magnetic plunger 2, and has a check valve 33 mounted in its upper end. Passages 34 are formed in the attaching flange 35 of piston 3| in order to form an unrestricted passage between interior of the plunger 2 and the interior of the cup I3.

In operation, starting with the parts in the positions illustrated with contacts 24, 25 closed and the plunger 2 at the top of its stroke, closure of the manual switch 2| energizes the solenoid 3 which draws the plunger downward cooking the spring I6. During this movement, liquid in the cylinder 21 is forced upwardly past the check valve 33 into the interior of the plunger 2. At the same time the liquid in the cup I3 outside of the cylinder 21 is permitted to flow up through the passages 34 so as to not interfere with the downward movement of the plunger 2.

As the plunger approaches the lower end of its stroke the contacts 24, 25 are opened in the manner set forth in the patent cited whereby solenoid sions of plunger 2 and solenoid 3, they may be designed to provide any desired output pr the volume of the output being-correspondingly reduced, of course, as the pressureis increased vll) The universal mounting of the cylinder 21 per:

mits compensation for any-misalignment pf the, piston 3| with plunger 2 and cylinder l, thereby insuring smooth and effective operation of the.

pump without reducing the normal manufacturing tolerances of commercial practice.

Although but one embodiment of the device has been shown and described .in detail it will ,be understcod that other embodiments are possible and changes may be made in the design and arrangement of the parts without departing .from the spirit of the invention.

1. In an electromagnetic reciprocating pump .a non-magnetic cylinder, a hollow magnetic plun i-eraslidably mounted therein, a solenoid surrounding the cylinder, :a casing enclosing the cylinder solenoid and having partitions forming inlet .and outlet chambers connected by said cylinder, 12:. cup having a check valve in its bottom extending into the inlet chamber and having a sealed '4 connection with the adjacent end of the cylinder, a spring in the cup pressing against the magnetic plunger, a buffer spring limiting the discharge stroke of the plunger, means including contacts controlled by the plunger for energizing the solenoid as the plunger approaches the end of the discharge stroke responsive to the pressure of said spring, and to deenerglze the Solenoid as th plunger approaches the end of the cocking stroke; .a pump cylinder sealed to the bottom of said cup, allollowpiston slidable in the pump cylinder fixed to the adjacent end of the magnetic plunger in alinement therewith and a check valve in said piston; the means for attaching the piston to the plunger being provided with a passage connecting the interior of the plunger with the interior ofsaid cup. 1

.2. A reciprocating pump as set forth in claim 1 including further a sealing ring in the bottom 01' the cup, and said pump cylinder having a flange with a surface bearing on the sealing ring, the plunger spring being seated on flange and serving to maintain the contact of the sealing surfaces while permitting universal movement 01 the pump cylinder.

K. DONALD AUMICK. JOHN W. DICKEX.

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